Polyurethane plastics



United States atent time 3,047,540 POLYURETHANE PLASTI'CS Rudolf Morten, Koln-Mulheim, Gunther Loew, Koln, and

Otto Bayer, Levericusen, Germany, assignors to Farbenr'abriken Bayer Aktiengesellschaft, Leverkusen, Germany, a corporation of Germany No Drawing. Filed Jan. 12, 1960, Ser. No. 1,878 Claims priority, application Germany Feb. 18, 1959 8 Claims. ((31. 260-775) This invention relates to polyurethane plastics and, more particularly, to a method for catalyzing the reaction between an organic isocyanate and an organic compound containing an active hydrogen-containing group.

Polyurethane plastics are prepared by reacting organic compounds containing active hydrogen-containing groups with organic polyisocyanates. If necessary, water or some other blowing agent is incorporated into the reaction mixture to produce a cellular polyurethane plastic. In the preparation of polyurethane plastics, organic compounds containing primary hydroxyl groups such as hydroxyl polyesters, polyhydric polyalkylene ethers, polyhydric polyalkylene thioethers and polyacetals are conventionally used. The primary hydroxyl groups react rapidly with isocyanate groups and, therefore, insure rapid formation of a cellular structure when the polyaddition reaction proceeds concurrently with the evolution of carbon dioxide from the reaction between the isocyanate groups and water. The secondary hydroxyl groups are less reactive and therefore, it is more diflicult to prepare polyurethanes therefrom.

Organic compounds containing predominantly secondary hydroxyl groups also have a lower initial viscosity than the organic polyisocyanates due to the less polar structure of this type of organic compound. It is, therefore, difiicult to achieve satisfactory mixing of organic compounds containing predominantly secondary hydroxyl groups so as to harmonizethe simultaneous reaction of the organic polyisocyanate with water to produce carbon dioxide and with the organic compound containing predominantly secondary hydroxyl groups to produce polymers so that a cellular structure results. For this reason it has been preferred to carry out the reaction between the organic polyisocyanate and the organic compound containing predominantly secondary hydroxyl groups in a first step to produce an initial adduct having terminal NCO groups and then react this initial adduct with water and, if necessary, additional organic polyisocyanate to produce the cellular polyurethane plastic. By carrying out the reactions in separate stages, it is possible to overcome the difliculty involved in trying to harmonize the reactions.

It is also possible to carry out the reaction between an organic compound containing predominantly secondary hydroxyl groups and an organic polyisocyanate with the concurrent production of carbon dioxide in a single working step provided that a strongly basic catalyst such as endoethylene piperazine is included in the reaction mixture. The presence of the strongly basic catalyst results in a substantial increase in secondary reactions such as polymerization reactions which undesirably influence the properties of the cellular polyurethane plastic produced.

It has been heretofore proposed in US. Patent 2,846,408

to employ nonbasic polyvalent metal salts of carboxylic acids or metal alcoholates as catalysts for the reaction between an organic polyisocyanate and an hydroxyl polyester. It is often necessary, in order to effectively catalyze the reaction with these compounds, to use critical amounts, if a stable cellular polyurethane plastic is to result. 1

It is, therefore, an object of this invention to provide an improved method of catalyzing the reaction between Patented July 31, 1962 an organic isocyanate and an organic compound containing at least one active hydrogen-containing group. Another object of this invention is to provide an improved method for the preparation of cellular polyurethane plastics. Another object of this invention is to provide an improved method of catalyzing the reaction between an organic polyisocyanate and an organic compound containing at least two active hydrogen-containing groups. Still another object of this invention is to provide a method of catalyzing the reaction between an organic polyisocyanate and an organic compound containing at least two active hydrogen-containing groups to produce a cellular polyurethane plastic. Still another object of this invention is to provide improved tin-containing catalysts for the preparation of cellular polyurethane plastics from organic polyisocyanates and organic compounds containing at least two active hydrogen-containing groups. Still another object of this invention is to provide improved cellular polyurethane plastics. A further object of the invention is to provide improved cellular polyurethane plastics obtained from an organic polyisocyanate and a polyhydric polyalkylene ether or thioether. Still another object of the invention is to provide improved cellular polyurethane plastics and an improved method for the preparation thereof from organic polyisocyanates and polyhydric polyalkylene ethers containing predominantly secondary hydroxyl groups.

The foregoing objects and others, which will become apparent from the following description, are accomplished in accordance with the invention, generally speaking, by providing a method of catalyzing the reaction between an organic isocyanate and an organic compound containing at least one active hydrogen-containing group as determined by the Zerewitinoif method, said active hydrogencontaining group being reactive with an -NCO group, wherein the said components are mixed in the presence of a chelate of tin having at least one carbon to tin bond and containing at least one tertiary nitrogen atom in at least one organic radical thereof. Thus, this invention contemplates a process for the preparation of polyurethane plastics by reaction of an organic polyisocyanate with an organic compound containing at least two active hydrogen-containing groups, said reaction being carried out in the presence of a tin chelate having at least one carbon to tin bond and containing at least one tertiary nitrogen atom in at least one organic radical thereof. In a preferred embodiment of the invention, cellular polyurethane plastics are produced by combining an organic polyisocyanate with an organic compound containing at least two active hydrogen-containing groups and a blowing agent, such as water or a halohydrocarbon, such as,

for example, dichlorodifiuorornethane, trifluorochloromethane and the like in the presence of a tin chelate containing at least one carbon to tin bond and containing at least one tertiary nitrogen atom in at least one organic radical thereof.

Any suitable tin chelate may be used provided that it contains at least one carbon to tin bond and at least one tertiary nitrogen atom in at least one organic radical thereof.

It is preferred to employ chelates of tetravalent tin in which each tin atom is attached to an organic radical by means of at least one carbon to tin bond. Any suitable organic radical may be used to form the carbon to tin bond including for example, aliphatic, oycloaliphatic, aromatic and heretocyclic radicals which may also be substituted with any other suitable substituent which does not interfere with the catalytic activity of the tin chelate, such as, for example, halogeno such as, for example, chloro, bromo, iodo, fluoro and the like; nitro; alkoxy such as, for example, methoxy, ethoxy, propoxy, butoxy, amoxy and the like; carboalkoxy such as, for example,

e) carbomethoxy, carbethoxy and the like; dialkyl amino such as, for example, dimethyl amino, diethyl amino, dipropyl amino, methylethyl amino and the like; mercapto; carbonyl; thiocarbonyl; hydroxy; phosphato; phosphoryl and the like.

When aliphatic radicals are the organic radicals, they may be for example, alkyl, alkenyl, aralkyl, aralkenyl, and the like.

Any suitable alkyl radical may be the organic radical such as, for example, methyl, ethyl, n-propyl, isopropyl, n-butyl, isobutyl, sec-butyl, t-butyl, n-amyl and various isomers thereof such as, for example, l-methyl-butyl, 2- methyl-butyl, 1,1-dimethylpropyl, 1,2-dimethylpropyl, 2,2- dimethylpropyl, l-ethylpropyl and the like and the corresponding straight and branched chain isomers of hexyl, heptyl, octyl, nonyl, decyl, undecyl, dodecyl, tridecyl, tetradecyl, pent-adecyl, :hexadecyl, heptadecyl, octadecyl, nondecyl, eicosyl and the like.

Any suitable alkenyl radical may be the organic radical such as, for example, ethenyl, l-propenyl, Z-propenyl, isopropenyl, l-butenyl, Z-butenyl, S-butenyl and the corresponding branched chain isomers thereof such as for example, l-isobutenyl, 2-isobutenyl, l-sec-butenyl, 2-secbutenyl, including l-methylene-Z-propenyl, l-pentenyl, 2- pentenyl, 3-pentenyl, 4-pentenyl and the corresponding branched chain isomers thereof; l-hexenyl, Z-hexenyl, 3- hexenyl, 4-hexenyl, S-hexenyl and the corresponding branched chain isomers thereof such as, for example, 3,3- dimethyl-l-butenyl, 2,3-dimethyl-1-butenyl, 2,3-dimethyl- Z-butenyl, 2,3-dimethyl-3-butenyl, l-methyl-l-ethyl-Z-propenyl and the various isomers of heptenyl, octenyl, nonenyl, decenyl, undecenyl, dodecenyl, tridecenyl, tetradecenyl, pentadecenyl, hexadecenyl, heptadecenyl, octadecenyl, nondecenyl, eicosenyl and the like.

, Any suitable aralkyl radical may be the organic radical such as, for example, benzyl, tx-phenyl-ethyl, fi-phenylethyl, a-phenyl-propyl, B-phenylpropyl, gamma-phenylpropyl, a-phenyl-isopropyl, IB-phenyl-isopropyl, aphenylbutyl, ,B-phenyl-butyl, gamma-phenyl-butyl, delta-phenylbutyl, a-phenyl-isobutyl, fi-phenyl-isobutyl, gamma-phenyl-isobutyl, a-phenyl-sec-butyl, B-phenyl-sec-butyl, gamma-phenyl-sec-butyl, fi-phenyl-t-butyl, u-naphthyl-methyl, 3'-naphthyl-methyl and the corresponding oc'- and ,8- naphthyl derivatives of n-amyl and the various positional isomers thereof such as, for example, l-methyl-butyl, 2- methyl-butyl, 3-methyl-butyl, 1,1-dimethyl-propyl, 1,2-dimethyl-propyl, 2,2-dimethyl-propyl, l-ethyl-propyl and said derivatives of the corresponding isomers of hexyl, heptyl, octyl and the like including eicosyl and the corresponding alkyl derivatives of phenanthrene, fluorene, acenaphthene, chrysene, pyrene, triphenylene, naphthacene and the like.

Any suitable aralkenyl radical may be the organic radical such as, for example, oc-phenyl-ethenyl, ,B-phenyl-ethenyl, u-phenyl-l-propenyl, fi-phenyl-l-propenyl, gammaphenyl-1-propenyl, ot-phenyl-2-propenyl, B-phenyl-Z-propenyl, gamma-phenyl-Z-propenyl, fl-phenyl-isopropenyl and phenyl derivatives of the isomers of butenyl, pentenyl, hexenyl, heptenyl up to and including eicosenyl and other aromatic derivatives of alkenyl, that is alkenyl radicals derived from naphthalene, phenanthrene, fluorene, acenaphthene, chrysene, pyrene, triphenylene, naphthacene and the like.

When cycloaliphatic radicals are the organic radicals, they may be for example, cycloalkyl, cycloalkenyl and the like.

Any suitable cycloalkyl radical may be the organic radical such as, for example, cyclopropyl, cyclobutyl, cycloamyl, cyclohexyl, cycloheptyl, cyclooctyl, cyclononyl, cyclodecyl, cycloundecyl, cyclododecyl, cyclotridecyl, cyclotetradecyl, cyclopentadecyl, cyclohexadecyl, cycloheptadecyl, cyclootadecyl, cyclonondecyl, cycloeicosyl, a-cyclopropyl-ethyl, B-cyclopropyl-ethyl, ot-cyclobutyl-propyl, [3- cyclobutyl-propyl, gamma-cyclobutyl-propyl, a-cycloamyl-isopropyl, B-cycloamyl-isopropyl and the like.

Any suitable cycloalkenyl radical may be the organic radical such as, for example, cyclopentenyl,a-cyclohexylethenyl, B-cyclohexyl-ethenyl, ot-cycloheptyl-l-propenyl, ,B-cycloheptyl-l-propenyl, gamma-cycloheptyl-l-propenyl, a-cyclQOctyl-Z-propenyl, fi-cyrilooctyl-Z-propenyl, gammacyclooctyl-Z-propenyl, ,B-cyclononyl-isopropenyl, ot-IIlEtlIlylene-B-cyclododecyl-ethyl, cyclopentadienyl and the like.

Where aromatic radicals are the organic radicals, they may be for example aryl, alkaryl and the like.

Any suitable aryl radical may be the organic radical such as, for example, phenyl, ot-naphthyl, fi-naphthyl, aanthryl, B-anthryl, gamma-anthryl including the various monovalent radicals of indene, isoindene, acenaphthene, fluorene, phenanthrene, naphthacene, chrysene, pyrene, triphenylene and the like.

Any suitable alkaryl radical may be the organic radical such as, for example, o-tolyl, m-tolyl, p-tolyl, 2,3-xylyl, 2,4-xylyl, 2,5-xylyl 2,6-xylyl 3,4-xylyl, 3,5-xylyl, o-cumenyl, m-cumenyl, p-cumenyl, mesityl, o-ethylphenyl, methylphenyl, p-ethylphenyl, Z-methyl-wnaphthyl, 3-methyl-ot-naphthyl, 4-methyl-a-naphthyl, S-meth l-a-naphthyl, 6-methyl-ot-naphthyl, 7-methyl-a-napht-hyl, S-mCthYl-unaphthyl, l-ethyl-;5'-naphthyl, S-ethyl-[i-naphthyl, 4-ethyl- B-naphthyl, S-ethyl-Bmaphthyl, 6-ethyl-B-naphthyl, 7-ethyl-fl-naphthyl, 8-ethyl-[3-naphthyl, 2,3-dipropyl-a-naphthyl, 5,8-diisopropyl-/3-naphthyl and the like.

When heterocyclic radicals are the organic radicals, they may contain any suitable hetero atom such as, for example, sulphur, oxygen and the like. Any suitable heterocyclic radical may, therefore, be the organic radical such as, for example, a-furfuryl, ;3-furfuryl, thienyl and the like.

The chelate forming or complex forming components which may be used to form the tin chelates of the present invention form a main-valency and secondary-valency bond with formation of ring systems which preferably have five or more members and most preferred are those with five or six ring members. Tetravalent tin compounds containing two organic radicals linked to tin through a carbon to tin bond are preferred, since a coordination number of six is obtained When the molecule is saturated. if three organic radicals are bonded to tin through a carbon to tin bond, then the coordination number of the resulting saturated compound is only five and if only one organic radical is bonded to tin through a carbon to tin bond, then a secondary-valency bond is not available to form a chelate complex. Compounds having only one organic radical bonded to tin through a carbon to tin bond may be used, however, if desired and if some other bonding provision is made to yield a coordination number which Will form a secondary-valency bond. The chelate forming compound, in other Words, contains (a) At least one group A which is linked to the tin atom through a main-valency bond. Such groups A are hydroxyl groups including keto groups in their enolic form and carboxyl groups, and

(b) In suitable above-outlined steric configuration at least one group B which provides for free electron pairs capable of forming a secondary-valency bond with the tin atom. Such groups B are CO-groups such as keto-, esterand amide groups, as Well as Schiffs base groups =N or other linkages O. The sulfur analoga can replace the described oxygen containing groups.

The chelate-forming components must contain a tertiary nitrogen atom and may be substituted in any desired manner provided the substituents do not interfere with the capacity of the compound to form a chelate complex with tin. Examples of suitable chelate-forming compounds are for example, B-diketones, o-hydroxyphenones, B-ketocarboxylic acid esters and the like containing tertiary amino atoms, such as, for example, 7-diethylaminoheptane-2,4-dione and the reaction products of B-diketones or [i-ketocarboxylic esters, such as acetyl acetone, 2-furoyl benzoyl methane, 2-thenoyl ace-tone, 2,2-dithenoyl methane, acetoacetic ester and the like with 1 mol of a haloalkyl dialkyl amine such as, for example, N-[i-chloroethyldimethyl amine in the presence of metallic sodium. Ex-

amples of such reaction products are S-(B-diethyaminoethyl) -acetyl acetone, x( ,B-diethylaminoethyl) -acetoacetic ethyl ester and the like. In these compounds the carbon atom in the central position should not be fully substituted, otherwise the compound may not form a chelate complex with tin. Also suitable as chelate-forming compounds are the transesterification products of fi-ketocarboxylic esters, such as, for example, acetoacetic ester, cyclopentanone-Z-carboxylic acid ethyl ester and the like with suitable aminoalcohols, such as, for example, dimethylamino ethanol, diethylamino ethanol, dibutylamino-ethanol, N-methyl-Nstearyl ethanolamine and the like as well as adducts of alkylene oxides, such as ethylene oxide, propylene oxide, butylene oxide and the like, such as, for example, methylethylamine, diethylamine and the like. Polyfunctional complex former-s containing several fi-ketoester groups in the molecule can be obtained in a simple manner by the trans-esterification of these adducts with polyfunctional amino alcohols, such as, for example, N-alkyl-diethanolamines such as, N-methyl-diethanolamine and the like, trialkaiiolamines, such as, triethanolamine and the like. Particularly suitable complex formers are acetoacetic-( 8-dimethylaminoethyl)-ester, acetoaceticfl-diethylamino) -ethyl ester, acetoaceticfi- N-methyl-N-stearylaminoethyl)ester, cyclopentanone 2- carboxylic-(fi-dibutylaminoethyl)-ester and N-methyl diethanolamine bis-(acetoacetic)-ester. Basically subs-tituted salicylaldehydes and naphthaldehydes, such as, for example, p-dimethylamino-salicylaldehyde, S-dimethylamino naphthaldehyde and the like can also be used as complex formers.

The catalysts employed in the process according to the present invention may be prepared in various ways. Thus, compounds of the general formula R Sn(OCH in which R is an organic radical as defined above and n is an integer from 1 to 3 and which are described in United States Patent No. 2,727,917 can be transesterified with the appropriate chelate former, methanol being split off. Another method of preparing the catalysts is by the reaction of a tin halide having the formula R Sn (halogen) in which R and n have the previously specified meanings with the chelate former with formation of, for example, K CO and with azeotropic removal of the water which is formed. By suitable choice of components and quantitative ratios, it is possible to produce linear or branched products of both low-molecular weight and highmolecular weight. The metal compounds can, of course, also be mixed in any desired manner.

Instead of tin compounds containing only one tetravalent tin atom in the molecule, it is also possible to use complexes of stannoxanes containing Sn-OSn-groupings in the molecule and in which each tin atom is attached to an organic radical by means of at least one carbon to tin bond.

The tin compounds, depending on their nature, are solid, amorphous, pasty or even liquid and viscous products, and may be added in several different Ways to the reaction components to be foamed. Thus, the liquid tin compounds are generally of good compatibility with the polyethers and polyesters and can be immediately added thereto. Solid tin compounds can be dissolved in solvents, such as acetone, aromatic hydrocarbons, chlorinated hydrocarbons and others or in 'one of the reaction components. They can, however, also be added in solid form to the reaction mixture to be foamed or in the form of a paste with the polyhydroxy compound. The quantities of catalyst which are necessary vary considerably and naturally depend on the nature and composition of the reaction mixture which is to be foamed. On the other hand, the active tin-content of the catalysts varies according to the tin compounds which are used. Generally speaking, the catalysts are employed in an amount of from about 0.001 percent to about 5.0 percent by Weight, based on the weight of the reaction mixture.

The tin catalysts of the present invention are particularly useful in the production of cellular polyurethane plastics. They represent an improvement over the heretofore known catalysts because lesser amounts are required to achieve the same effect and, moreover, they do not exert adverse effects on the final product.

Any suitable organic compound containing at least one active hydrogen-containing group as determined by the Zerewitinoif method, said group being reactive with an NCO group, may be used for reaction with organic isocyanates. Suitable compounds include, therefore, alcohols, phenols, polyhydric alcohols, polyhydric polyalkylene ethers, polyhydric polyalkylene thioethers, hydroxyl polyesters, hydroxyl polyester amides, polyacetals and the like.

Generally speaking, all the heretofore known organic compounds containing an active hydrogen-containing group which will react with an -NCO group are contemplated. The presence of these groups may be determined by the well-known Zerewit'inoff method, I. Am. Chem. Soc, 49, 3181 (1927). containing groups may be, for example, hydroxyl groups, primary amino groups, secondary amino groups, carboxy groups (-COOH), mercapto groups, enolizable methylene groups and the like.

Therefore, any of the alcohols, phenols, amines and the like set forth above may be reacted with an organic isocyanate in the presence of the tin compounds of the present invention. The invention, therefore, contemplates the alcohols, phenols, and the like obtained by adding one or more of the above-defined groups to any of the organic radicals set forth above. The invention, therefore, contemplates the catalysis of the reaction between any organic compound having an active hydrogen-containing group and an organic isocyanate including the reaction of methanol, ethanol, ethyl amine, phenol, aniline, acetic acid and the like with any of the isocyanates disclosed below.

In a preferred embodiment of the invention organic compounds containing at least two active hydrogen-containing groups as defined above are reacted with organic polyisocyanates in the presence of the organo-tin compounds to prepare polyurethane plastics. This procedure is best adapted to the production of cellular polyurethane plastics.

The organic compounds containing at least two active hydrogen-containing groups may, therefore, be prepared from alkylene oxides such as, for example, propylene oxide, butylene oxide, 1,2-amylene oxide, and the like as well as aralkylene oxides such as, for example, styrene oxide. The epihalohydrins may also be used, such as, for

- example, epichlorohydrin and the like. Also, organic com pounds containing at least two active hydrogen-containing groups may be prepared by condensing one of the aforementioned types of oxides with any suitable polyhydric alcohol such as, for example, alkane diols such as, for example, ethylene glycol, l,3-propane diol, 1,4-butane diol, 1,3-butane diol, 1,2-isopropane diol, 1,3-isobutane diol, 1,5-pentane diol, l-methyl pentane-l,4-diol, 1,6-hexane diol, 1,7-heptane diol, 1,8-octane diol, 1,15-pentadecane diol and the like, alkane triols such as, for example, 1,3,6- hexanetriol, glycerine and the like, alkane polyols such as sorbitol, alkene diols such as, for example, 1,2-ethene diol, l-butene-1,4diol, propene-l,3-diol and the like, alkine diols such as, for example, l,3-butadiene-1,4-diol, polyhydric others such as, for example, trimethylol propane, pentaerythritol, polyethylene ether glycols, polypropylene ether glycols and the like and phenols such as, for example, hydroquinone, 4,4'-dihydroxy diphenyl methane, 4,4- dihydroxy diphenyl dimethyl methane, 1,5-dihydroxy naphthalene and the like. Also one may condense the aforementioned oxides With aliphatic or aromatic polyamines such as, for example, alkylene diamines such as, for example, ethylene diamine and the like, alkylene triamines such as, for example, triethylene diamine and the like, aromatic amines such as, for example, aniline, pamino aniline and the like and heterocyclic amines such as, for example, piperazine and the like. Condensation Therefore, the active hydrogensoy/ps products of the aforementioned oxides with amino alcohols such as, for example, alkanol amines such as, for example, ethanol amine and the like, N-alkyl alkanol amines such as, for example, N-methyl ethanol amine and the like, dialkanol amines such as, for example, diethanol amine and the like, N-alkyl dialkanol amines such as, for example, N-methyl diethanol amine, trialkanol amines such for example, triethanol amine and the like, N,N,N',l ltetrakis (Z-hydroxy propyl) ethylene diamine and the like and phenol amines such as, for example, p-amino phenol and the like may also be used. One may also employ condensation products of the aforementioned oxides with hydroxyl polyesters such as are obtained for example from polycarboxylic acids and polyhydric alcohols or the reaction product of castor oil, sugar or the like. Any suitable polycarboxylic acid may be used such as, for example, malonic acid, succinic acid, glutaric acid, adipic acid, phthalic acid, terephthalic acid, sebacic acid, suberic acid, maleic acid, itaconic acid and the like. Any suitable polyhydric alcohol may be used such as, for example, 1,4- butane diol, trimethylol propane, pentaerythritcl or the like. Polyesters prepared from these components may be used Without modification with the oxides. It is preferred that they have terminal hydroxyl groups.

Ethylene oxide may be partially incorporated into the oxides recited above by carrying out the condensation of the oxides recited above in the presence of ethylene oxide or by subsequently condensing the polymers recited above with ethylene oxide. The resulting polyhydroxy compounds containing a minor proportion of ethylene oxide do not differ substantially from the aforementioned polyhydroxy compounds as regards their reactivity with respect to polyisocyanates. Polyhydroxy compounds containing secondary hydroxyl groups can also be produced by esterifyinv one or more of the previously mentioned pclyalcohols, some of which may already contain secondary hydroxyl groups, with a deficient quantity of a polyoarboxylic acid, such as succinic acid, adipic acid, sebacic acid, dimerized and trimerized fatty acids, phthalic acid, maleic acid and fumaric acid, it being possible simultaneously to incorporate tertiary nitrogen atoms or carbonamide groups into the polyesters by the concurrent use of amino alcohols. In addition to the preferred polyhydroxy compounds containing secondary hydroxyl groups, it is also possible to use compounds which contain primary hydroxyl groups. Such compounds can for example be ob tained by the esterification of the aforementioned primary polyalcohols or amino alcohols with the aforementioned polycarboxylic acids. This group of compounds also includes a wide variety of polyethers, such as those derived from ethylene glycol, tetrahydrofuran and also thiodiglycol as well as various polyacetals, such as are obtained for example from polyhydric alcohols, such as, for example, ethylene glycol and the like disclosed above and aldehydes, such as formaldehyde.

The linear and branched organic compounds containing active hydrogen-containing groups employed in the process according to the present invention should have an acid number below about and preferably from 0 to about 2 when they are derived from polyesters. All types of the organic compounds containing at least two active hydrogen-containing groups should preferably have a molecular weight of at least about 500 and an OH equivalent of from about 100 to about 3000 if the only active hydrogen groups are hydroxyl groups. By OH equivalent is meant the amount of the compound in grams which contains 1 mol of hydroxyl groups. The aforementioned compounds may be mixed in any desired manner with the organic isocyanate. They may also be employed in admixture with the aforementioned lowmolecular Weight compounds provided the -OH equivalent of the mixture is between about 100 and about 3000.

Any suitable organic isocyanate may be used including aliphatic, cycloaliphatic, alkaryl, aralkyl, heterocyclic and arvl monoand polyisocyanates, such as, for example,

ethyl isocyana-te, propyl isocyanate, butyl isocyanate, pentyl isocyanate, hexyl isocyanate, heptyl isocyanate, octyl isocyanate and the like including eicosyl isocyanate. As diisocyanates, there may be used tetramethylene diisocyanate, pentamethylene diisocyanate, octamethylene diisocyanate, dodecamethylene diisocyanate, 3,3'-diisocyanato dipropyl ether, cyclollexyl isocyanate, tetrahydro-anaphthyl isocyanate, tetrahydro-B-naphthyl isocyanate, xylylene diisocyanates, p,p-diphenylmethane diisocyanate, fl,,8'-diphenylpropane 4,4-d.iisocyanate and the like. Other examples are bcnzyl isocyanate, undecamethylene diisocyanate, p-isocyanato benzyl isocyanate, phenyl isocyanate, p-dodecyl phenyl isocyanate, 5-dodecyl-2-methyl phenyl isocyanate, 3-nitro-4-dodecyl phenyl isocyanate, p-cetyloxy phenyl isocyanate, m-phenylene diisocyanate, p-phenylcne diisocyanate, l-methyl phenylene 2,4-diisocyanate, naphthylene 1,4-diisocyanate, naphthylene 1,5- diisocyanate, 2,6-toluylene diisocyanate, 1,3,5benzene triisocyanate, p,p,p"-triphenylmethane triisocyanate, tetrahydrofurfu'ryl isocyanate and the like.

Also the addition products of polyisocyanates with a deficient quantity of a low-molecular Weight alcohol, such as 1,4-butane diol, glycerine, trimethylol propane, the hexanediols and hexanetriols and addition products of the aforementioned polyisocyanates with low-molecular weight polyesters, such as castor oil, may also be used, as well as the reaction products of the aforementioned polyisocyanates with acetals as described in copendingapplication Serial No. 821,360. Also suitable are the isocyanate polymers described in German patent specifications Nos. 1,022,789 and 1,027,394, as laid open to inspection. Mixtures of organic isocy anates may also be employed. The process according to the present invention can also be used for the foaming of the initial adducts obtained from the aforementioned organic cornpounds containing at least two active hydrogen-containing groups and an excess of polyisocyanate by adding water.

The cellular polyurethane plastics are produced in accordance with the invention by the simultaneous intensive mixing of the components including the organic compound containing at least two active hydrogen-containing groups, the organic polyisocyanate and the tin compound together with water and/or other additives. The mixing of these components is preferably effected mechanzically for example in the manner described in US. Reissue Patent 24,514 to Hoppe et al. issued August 12, 1958. It is also possible to prepare a prepolyrner by reaction of the organic polyisocyanate and the organic compound containing at least two active hydrogen-containing groups in a first step and then reacting the resulting isocyanate terminated prepolymer with water in a second step in the presence of the tin compounds of the present invention to prepare a cellular polyurethane plastic.

A wide range of diiferent additives can be added to the reaction mixture in the production of cellular polyurethane plastics. Thus, it is sometimes convenient to use emulsifiers such as, for example, sulfonated castor oil and/or adducts of ethylene oxide with hydrophobic compounds containing one or more active hydrogen atoms, foam stabilizers such as, for example, siloxane oxyalkylene block copolymers having the formula ()(R2SiO) (OnH2nO): wherein R, R and R" are alkyl radicals having 1 to 4 carbon atoms; p, q and r each have a value of from 4 to 8 and (C I-I O) is a mixed polyoxyethylene oxypr pylene block containing from 15 to 19 oxyethylene units and from 11 to 15 oxypropylene units with 2 equal to from about 26 to about 34 or similar stabilizer. A process which combines the catalyst and this stabilizer is contemplated by the invention as a preferred embodiment. Silicone compounds represented by the above formula and a method for making them are disclosed in U.S. Pattent 2,834,748 to Bailey et al.

Accelerator compounds containing basic nitrogen in the molecule may also be used as additive compounds which will aid in the production of regular pore size in the final product such as, for example, paraifin oils and a variety of silicone oils such as, for example, dimethyl polysiloxanes and the like, in addition to dyestuifs, fillers, flame-proofing agents and plasticizers.

The tin catalyst of the present invention may also be employed with the heretofore known basic accelerators such as, for example, tertiary amines such as, for example, dimethyl benzylamine, 1-ethoxy-3-dimethylaminopropane, endoethylene piperazine in small quantities, permethylated N ethylaminopiperazine and dimethyl ethyl amine as well as metal compounds such as, for example, alkali metal hydroxides such as, for example, sodium hydroxide, alkali metal carbonate such as, for example, sodium carbonates, alkali metal phenolates such as, for example, sodium phenoxide and alkali metal alcholates such as, for example, sodium methoxide.

The cellular polyurethane plastics produced in accordance with the present invention have excellent mechanical and physical properties and their bulk density can be modified in known manner by varying the quantity of polyisocyanate and Water employed in their production. Cellular polyurethane plastics may be used in a variety of commercial applications including both thermal and sound insulation, cushions, upholstery units, crash pads and arm rests for automobiles and the like. Non-porous polyurethane plastics have good abrasion and tear resistance and can be used in the production of gears, gaskets, driving members, accumulation bladders, automobile tires and a whole host of other applications.

The invention is further illustrated by the following examples in which the parts are by weight unless otherwise indicated.

Example 1 (a) About 0.5 mol of CH -O[Sn(C H O] Cl-I in which n=about 1.5 are trans-esterified with about 1 mol of u-(B-diethylaminoethyl)acetoacetic acid ethyl ester at a maximum temperature of about 130 C. in water jet vacuum with exclusion of moisture and while distilling oil the calculated quantity of methanol. A yellow viscous oil is thereby obtained in the calculated quantity.

(b) About 100 parts of a linear polypropylene glycol having an OH number of about 51, about 43 parts of a toluylene diisocyanate containing the 2,4- and 2,6-isomers in a ratio of 80:20, about 1.5 parts of a water-soluble silicone-ethylene oxide c-opolymer, about 1.0 part of the tin complex compound produced as described in Example 1(a) and about 3.5 parts of Water are mixed with one another in the usual manner, and after being placed in a mold, produce a rapidly setting foam material with good elastic properties and Without any tendency to shrink.

' Example 2 (a) About 130 parts of acetoacetic ester and about 117 parts of N,N-diethylethanolamine are trans-esterified with exclusion of moisture in a column, whereby the calculated quantity of ethanol is obtained, together with small quantities of aectone. After distillation using an oil pump, the residue yields approximately 110 parts of acetoacetic- (,B-diethylaminoethyl)ester having a boiling point at 0.1 mm. Hg of about 83-87 C. and an n :1.4500.

(b) About 75 parts of the acetoacetic-(,B-diethylaminoethyl)-ester thus obtained and about 55.4 parts of dibutyl dimethoxy tin are trans-esterified with exclusion of moisture and up to a maximum temperature of about 130 C., finally in vacuo at about 20 mm. Hg. In this way, the theoretical quantity of methanol is distilled off and there is obtained a yellowish viscous product having a refractive index of 11 1.5008.

(0) About parts of a polyester of adipic acid, diethylene glycol and hexanetriol having an OH number of about 56, an acid number of about 1.3 and a viscosity of about 18,000 cp. at 25 C., about 43 parts of a toluylene diisocyanate containing the 2,4- and 2,6-isomers in a ratio 65:35, about 0.5 part of the tin complex salt obtained as described under 2(b), about 1.5 parts of an approximately 50% aqueous solution of the sodium salt of sulphonated castor oil, about 1.5 parts of an approximately 50% aqueous solution of the sodium salt of sulphonated ricinoleic acid and about 2.0 parts of water are mixed with one another in the usual manner and, after being discharged, yield a foam which rises in about 2 minutes, sets in approximately 15-20 minutes and which has excellent elastic properties.

Example 3 (a) About 380 parts of a-(fi-diethylaminoethyl)acetoacetic ethyl ester and about 250 parts of dibutyl dimethoxy tin are trans-esterified as described in Example 2(1)) to give a quantitative yield of a tin complex salt having a refractive index 11 1.4932.

(b) About 100 parts of a polypropylene glycol obtained by the addition of propylene oxide to trimethylol propane and having an OH number of about 55.8, about 42 parts of the toluylene diisocyanate employed in Example 1, about 1.5 parts of the silicone oil employed in Example 1(b), about 1.5 parts of the tin complex salt prepared as described in Example 3(a) and about 3.3 parts of water are foamed in the manner described in French patent specification No. 1,074,713 and provide a foam material which sets after approximately 30 minutes, and which has excellent elastic properties.

Example 4 Similar results were obtained by replacing the silicone employed in Example 3(b), by about 1.5 parts of a basic silicone oil haivng the formula and obtained by the trans-esterification of the corresponding diethoxy compound of the formula C H O [Si CH O] il- H (molecular weight about 700) with about 2 mols of ethanolamine.

Example 5 (a) About 52 parts of ethyl acetoacetate and about 130.8 parts of N-methyl-N-stearyl-ethanolamine are transes'terified with exclusion of moisture at about C. and finally in vacuo, the theoretical quantity of ethanol being distilled off. About 59 parts of dibutyl dimethoxy tin are then added and the theoretical quantity of methanol is again trans-esterified at about C., finally in vacuo. There are thus obtained about 207 parts of a slowly solidifying oil having a refractive index n :1.4-862.

(b) About 100 parts of a polyether isocyanate having an NCO content of about 8.1% and a viscosity of about 8000 cp. at 25 C. such as obtained by reacting. about 70 parts of a linear polypropylene glycol having an OH number of about 54.6 and about .30 parts of the polypropylene glycol employed in Example 3(b) with about 34.4 parts of the toluylene diisocyanate employed inExample 1(b), about 0.1 part of the silicone oil employed in Example 4, about 1.8 parts of .water and about 0.8 par-t of the tin complex produced as described in Example 5(a) are stirred and cast to yield a foam having a rising time of about 90 seconds, good elastic values and a high tearing strength.

Example 6 answer) of hexanetriol and propane-1,2-diol in a molar ratio of about 1:1 and having an OH number of about 56, about 35.5 parts by volume of the toluylene diisocyanate employed in Example 1(b), about 3.0 parts of Water, about 1.5 parts of the water-soluble silicone oil employed in Example 1(b) and about 1.0 part of the tin complex salt prepared as described in Example (a) are mechanically mixed in the apparatus described in French patent specification No. 1,074,713 and yield a rapidly rising foam having a setting time of about 20 minutes, and good elastic properties.

Physical properties:

Bulk density 31 kg./ 111. Tensile strength 0.9 kg./cm. Breaking elongation 330%. Elasticity 45%. Permanent deformation 14 (22 hours at 70;

/2 hour recovery).

It is to be understood that any of the other isocyanates, organic compounds containing active hydrogen-containing groups, tin chelate or other additive described herein can be substituted for the ones used in the preceding examples with equally satisfactory results.

Example 7 100 parts by weight of the polypropylene glycol of Example 6, 38 parts by weight of toluylene diisocyanate, 1.5 parts by weight of the polysiloxane of Example 1, 2.9 parts by weight of water and 1 part by weight of the dibutyl tin-bis-(aceto acetic acid-fi-diethyl amino ethylester)-cornplex of Example 2, are mechanically mixed in the apparatus described in French patent specification 1,074,713. The foam rises quickly within 1.5 minutes and sets within minutes.

Bulk density kg./m. 36 Tearing strength kg./cm. 1.1 Elongation at break percent 385 Elasticity do 51 Permanent elongation do 40 7 Example 8 100 parts by weight of the polypropylene glycol of Example 6, 38 parts by weight of toluylene diisocyanate, 1 part by weight of the polysiloxane of Example 1, 2.8 parts by weight of water and 1.2 parts by weight of a dioctyl tin compound prepared by transesterification of 13 parts by weight of aceto acetic acid ester, 31.3 parts by weight of N-methyl-N-stearyl-ethanol amine and 25.5

parts by weight of dioctyl dimethoxy tin up to 130 C.

and having a refraction index 11 1.4823, are mixed together. The mixture results in a rapidly rising foam without cracks and shrinks and with good elastic properties.

Example 9 100 parts by weight of the polypropylene glycol of Example 6, 38 parts by weight of toluylene diisocyanate, 1 part by weight of the polysiloxane of Example 1, 2.8 parts by weight of water, 0.5 part by weight of N-ethyl morpholine, and 2 parts by weight of the dibenzyl tin complex, prepared by transesterification of 31.3 parts by weight of N-methyl-N-stearyl-ethanol amine with 13 parts by weight of aceto acetic acid ester and 18.2 parts by weight of dibenzyl dimethoxy tin up to 130 C. and having a refraction index n 1.5095 are mechanically mixed and result in a rapidly hardening foam.

It is possible to use instead of the above dibenzyl tin compound the corresponding triethyl tin compound.

Although the invention has been described in considerable detail for the purpose of illustration, it is to be understood that variations may be made therein by those skilled in the art without departing from the spirit of the invention and the scope of the claims.

The term tertiary nitrogen atom as used throughout the specification and claims means a nitrogen atom that is attached to three other atoms including three carbon atoms, two carbon atoms and one, sulfur atom, two carbon atoms and one nitrogen atom'and'the like. i

What is claimed is:

1. The method of catalyzing the reaction between an organic isocyanate and an organic compound containing at least one active hydrogen-containing group as determined by the Zerewitinofl? method which comprises mixing said materials in the presence of a catalytic amount of an organotin chelate chelated with an organic chelating agent and containing at least one carbon to tin bond and containing at least one tertiary nitrogen atom, the arrangement of the tertiary nitrogen and the tin in the compound being such that each of these functions as a catalyst in the reaction.

. The method of catalyzing the reaction between an organic polyisocyanate and an organic compound containing active hydrogen-containing groups, said groups being selected from the group consisting of hydroxyl groups, primary amino groups, secondary amino groups, carboxy groups and mercapto groups which comprises mixing said materials in the presence of a catalytic amount of an organo-tin chelate chelated with an organic chelating agent and containing at least one carbon to tin bond and containing at least one tertiary nitrogen atom, the arrangement of the tertiary nitrogen and the tin in the compound being such that each of these functions as a catalyst in the reaction.

3. The method of catalyzing the reaction between an organic polyisocyanate and an organic compound containing at least two active hydrogen-containing groups, said groups being selected from the group consisting of hydroxyl groups, primary amino groups and secondary amino groups to prepare a polyurethane plastic which comprises mixing said materials in the presence of a catalytic amount of an organo-tin chelate chelated with an organic chelating agent and containing at least one carbon to tin bond and containing at least one tertiary nitrogen atom, the arrangement of the tertiary nitrogen and the tin in the compound being such that each of these functions as a catalyst in the reaction.

4. The method of catalyzing the reaction between an organic polyisocyanate and an organic compound containing at least two active hydrogen-containing groups, said active hydrogen-containing groups being predominantly secondary hydroxyl groups, and water to prepare a cellular polyurethane plastic which comprises mixing said materials in the presence of a catalytic amount of an organo-tin chelate chelated with an organic chelating agent and containing at least one carbon to tin bond and containing at least one tertiary nitrogen atom, the arrangement of the tertiary nitrogen and the tin in the compound being such that each of these functions as a catalyst in the reaction.

5. The method of catalyzing the reaction between an organic isocyanate and an organic compound containing at least one active hydrogen-containing group which comprises mixing said materials in the presence of a catalytic amount of an organo-tin chelate selected from the group consisting of tetravalent tin chelates of ,6-diketones, ohydroxyphenones and acetoacetic esters, said chelates containing at least one carbon to tin bond and containing at least one tertiary nitrogen atom, the arrangement of the tertiary nitrogen and the tin in the compound being such that each of these functions as a catalyst in the reaction.

6. The method of catalyzing the reaction between an organic polyisocyanate and an organic compound containing at least two active hydrogen-containing groups as determined by the Zerewitinofi? method which comprises mixing said materials in the presence of a catalytic amount of a dialkyl tin chelate chelated with an organic chelating agent and containing at least one tertiary nitrogen atom, the arrangement of the tertiary nitrogen and the tin in 13 the compound being such that each of these functions as a catalyst in the reaction.

7. The method of catalyzing the reaction between an organic polyisocyanate and an organic compound containing at least two active hydrogen-containing groups as determined by the Zerewitinofi method which comprises mixing said materials in the presence of a catalytic amount of dibutyl tin bis-[aceto acetic (,B-diethylamino ethyl) ester]. 7

8. In a process for the preparation of a cellular polyurethane plastic by a process which comprises reacting an organic polyisocyanate with a polyhydric polyalkylene ether and water, the improvement which comprises mixing said reactants with from about 0.001 percent to about 5 percent by weight of a dialkyl tin chelate chelated with an organic chelating agent and containing at least one tertiary nitrogen atom, the arrangement of the tertiary nitrogen and the tin in the compound being such that each of these functions as a catalyst in the reaction.

References Cited in the file of this patent Mohay Publication: A One Shot System For Flexible Polyether-Urethane Foams, Nov. 10, 1958. 

1. THE METHOD OF CATALYZING THE REACTION BETWEEN AN ORGANIC ISOCYANNE AND AN ORGANIC COMPOUND CONTAINING AT LEAST ONE ACTIVE HYDROGEN-CONTAINING GROUP AS DETERMINED BY THE ZEREWITNOFF METHOD WHICH COMPRISES MIXING SAID MATERIALS IN THE PRESENCE OF A CATALYSTIC AMOUNT OF AN ORGANO-TIN CHELATE WITH AN ORGANIC CHELATING AGENT AND CONTAINING AT LEAST ONE CARBON TO TIN BOND AND CONTAINING AT LEAST ONE TERITARY NITROGEN ATOM, THE ARRANGEMENT OF THE TERTIARY NITROGEN AND THE TIN IN THE COMPOUND BEING SUCH THAT EACH OF THESE FUNCTIONS AS A CATALYST IN THE REACTION. 